Incoming Dem lawmaker mocks Trump for referring to himself as 'President T'

Rep.-elect Joe CunninghamJoseph CunninghamThe 31 Trump districts that will determine the next House majority Congressman blasts air horn at Trump official who said seismic air gun tests don't harm whales House passes second major gun bill MORE (D-S.C.) on Sunday mocked President TrumpDonald John TrumpJoint Chiefs chairman denies report that US is planning to keep 1K troops in Syria Kansas Department of Transportation calls Trump 'delusional communist' on Twitter Trump has privately voiced skepticism about driverless cars: report MORE for referring to himself as "President T" in a tweet in which he thanked himself for dropping oil prices. 

"Just changed Boone’s diaper (thank you Congressman C)," Cunningham, who won a seat in the House of Representatives earlier this month, tweeted. 

Trump on Sunday nicknamed himself "President T" in an early-morning tweet in which he lauded his work to reduce oil prices.  

“So great that oil prices are falling (thank you President T),” the president wrote. “Add that, which is like a big Tax Cut, to our other good Economic news. Inflation down (are you listening Fed)!”

The message came only days after he praised Saudi Arabia for the falling price of oil, before urging that the prices "go lower!"

Trump's relationship with Saudi Arabia has received heightened scrutiny in recent days. He said last week that the U.S. would seek to maintain a "steadfast" alliance with the kingdom despite its role in the killing of journalist and U.S. resident Jamal Khashoggi. 

Trump also refused to blame Saudi Crown Prince Mohammed bin Salman for the killing, even as reports emerged that the CIA has concluded that bin Salman likely ordered the assassination. 

Khashoggi was killed after entering the Saudi consulate in Istanbul on Oct. 2. 

Cunningham won his bid to represent South Carolina's 1st Congressional District earlier this month. He beat Republican state Rep. Katie Arrington to earn the seat that was left vacant after GOP Rep. Mark Sanford lost his primary.